Random blown heavy fuse usually a wire worn through at a sharp metal edge somewhere shorts when you hit a bump.

Very hard to find but sometimes you can by shaking what wire looms you can reach.

Could be harder: one of my nephews put a coin into my dad's cigarette lighter. It would blow the fuse on random bumps. Took a couple months to figure out

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2011 E70 • N55 (me)
2012 E70 • N63 (wife)